1. Technical Field
The present disclosure relates to a phase change memory cell and a phase change memory.
2. Description of Related Art
Generally, semiconductor memory devices are categorized as random access memories (RAMs) or read-only memories (ROMs). ROMs are nonvolatile memory devices such as PROMs (programmable ROMs), EPROMs (erasable PROMs), EEPROMs (electrical EPROMs), and flash memory devices, which retain their stored data even when their power supplies are interrupted. New types of RAMs containing nonvolatile memory devices have recently been introduced. Examples includes ferroelectric RAMs (FRAMs) employing ferroelectric capacitors, magnetic RAMs (MRAMs) employing tunneling magneto-resistive (TMR) films, and phase change memories (PCM) using chalcogenide alloys. Among these, the phase change memory cannot only be widely used in civilian areas of microelectronics such as mobile phones, digital cameras, MP3 players, and mobile memory, but also has important applications in aerospace, missile systems, and military field in the future. The phase change memory devices are relatively easy to fabricate, and thus phase change memory devices may provide the best opportunities in the actual implementation of high-capacity, low cost nonvolatile RAMs.
In traditional phase change memory cell, a heating element is used to heat the phase change material. During the dynamic storage, the heating element heats the phase change material to produce phase transition. However, one problem is that the heating element is made of metal or semiconductor, so it is prone to damage or oxidation during the cycle of heating process. Thus the lifespan of phase change memory cell will be affected. Furthermore, the heating element is formed by sputtering or vapor deposition, this process is complex and the production cost is relatively high.
What is needed, therefore, is to provide a phase change memory cell and a phase change memory that can overcome the above-described shortcomings.